Substrate Design for Semiconductor Packages and Method of Forming Same

ABSTRACT

An embodiment device package includes a package substrate and a first and a second die bonded to the package substrate. The package substrate includes a build-up portion comprising a first contact pad and a plurality of bump pads. The package substrate further includes an organic core attached to the build-up portion, a through-via electrically connected to the first contact pad and extending through the organic core, a second contact pad on the through-via, a connector on the second contact pad, and a cavity extending through the organic core. The cavity exposes the plurality of bump pads, and the first die is disposed on the cavity and is bonded to the plurality of bump pads.

PRIORITY CLAIM AND CROSS-REFERENCE

This application is a continuation-in-part of U.S. patent applicationSer. No. 14/181,305, filed Feb. 14, 2014, which application is herebyincorporated herein by reference.

BACKGROUND

In an aspect of integrated circuit packaging technologies, individualsemiconductor dies may formed and are initially isolated. Thesesemiconductor dies may then be bonded together, and the resulting diestack may be connected to other package components such as packagesubstrates (e.g., interposers, printed circuit boards, and the like)using connectors on a bottom die of the die stack.

The resulting packages are known as Three-Dimensional IntegratedCircuits (3DICs). Top dies of a die stack may be electrically connectedto the other package components through interconnect structures (e.g.,through-substrate vias (TSVs)) in bottom dies of the die stack. However,existing 3DIC packages may include numerous limitations. For example,the bonded die stack and other package components may result in a largeform factor and may require complex heat dissipation features. Existinginterconnect structures (e.g., TSVs) of the bottom die may be costly tomanufacture and result in long conduction paths (e.g., signal/powerpaths) to top dies of the die stack. Furthermore, solder bridges,warpage, and/or other defects may result in traditional 3DICs,particularly in packages having a high density of solder balls (e.g.,package-on-package (PoP) configurations), thin package substrates, andthe like.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It isnoted that, in accordance with the standard practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may be arbitrarily increased or reduced for clarity ofdiscussion.

FIGS. 1A through 1N illustrate cross-sectional views of variousintermediary stages of manufacturing a semiconductor package inaccordance with some embodiments;

FIG. 2 illustrates a cross-sectional view a semiconductor package inaccordance with some alternative embodiments;

FIGS. 3A through 3E illustrate cross-sectional views of variousintermediary stages of manufacturing a semiconductor package inaccordance with some alternative embodiments;

FIGS. 4A through 4L illustrate prospective views of various intermediarystages of manufacturing a package substrate in accordance with someembodiments;

FIGS. 5A and 5B illustrate cross-sectional views of semiconductorpackages in accordance with some alternative embodiments;

FIGS. 6A and 6B illustrate cross-sectional and top down views of apackage substrate in accordance with some alternative embodiments;

FIGS. 7A and 7B illustrate cross-sectional views of a device packageincorporating a package substrate in accordance with some alternativeembodiments;

FIGS. 8A through 8N illustrate varying views of various intermediarystages of manufacturing a package substrate in accordance with somealternative embodiments;

FIGS. 9A and 9B illustrate cross-sectional views of a device packageincorporating a package substrate in accordance with some alternativeembodiments;

FIG. 10 illustrate cross-sectional views of a device packageincorporating a package substrate in accordance with some alternativeembodiments;

FIGS. 11A and 11B illustrate cross-sectional views of a device packageincorporating a package substrate in accordance with some alternativeembodiments; and

FIG. 12 illustrates a process flow for forming a package in accordancewith some alternative embodiments.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the provided subjectmatter. Specific examples of components and arrangements are describedbelow to simplify the present disclosure. These are, of course, merelyexamples and are not intended to be limiting. For example, the formationof a first feature over or on a second feature in the description thatfollows may include embodiments in which the first and second featuresare formed in direct contact, and may also include embodiments in whichadditional features may be formed between the first and second features,such that the first and second features may not be in direct contact. Inaddition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

Further, spatially relative terms, such as “beneath,” “below,” “lower,”“above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly.

Various embodiments may include a plurality of first dies (e.g., memorydies) electrically connected to one or more second dies (e.g., logicdies) through first input/output (I/O) pads and redistribution layers(RDLs) formed on the second dies. The resulting die stack may be bondedto another package component such as an interposer, package substrate,printed circuit board, and the like through second I/O pads and the RDLsof the second dies. The package substrate may include a cavity, and thefirst dies may be disposed in the cavity. Thus, a three-dimensionalintegrated circuit (3DIC) such as a chip on fan-out package may be madewith a relatively small form factor at a relatively low cost and havingrelatively short conduction paths (e.g., signal/power paths).Furthermore, one or more heat dissipation features may be independentlyformed on opposite surfaces of the first and/or second dies.

FIGS. 1A through 1N illustrate cross-sectional views of variousintermediary stages of manufacturing an integrated circuit (IC) package100 (see FIG. 1N) in accordance with various embodiments. FIG. 1Aillustrates a plurality of dies 10. Dies 10 may include a substrate,active devices, and interconnect layers (not shown). The substrate maybe a bulk silicon substrate although other semiconductor materialsincluding group III, group IV, and group V elements may also be used.Alternatively, the substrate may be a silicon-on-insulator (SOI)substrate. Active devices such as transistors may be formed on the topsurface of the substrate. Interconnect layers may be formed over theactive devices and the substrate.

The interconnect layers may include an inter-layer dielectric(ILD)/inter-metal dielectric layers (IMDs) formed over the substrate.The ILD and IMDs may be formed of low-k dielectric materials having kvalues, for example, lower than about 4.0 or even about 2.8. In someembodiments, the ILD and IMDs comprise silicon oxide, SiCOH, and thelike.

A contact layer 12 including one or more contact pads is formed over theinterconnect structure and may be electrically coupled to the activedevices through various metallic lines and vias in the interconnectlayers. Contact pads in contact layer 12 may be made of a metallicmaterial such as aluminum, although other metallic materials may also beused. A passivation layer (not shown) may be formed over contact layer12 out of non-organic materials such as silicon oxide, un-doped silicateglass, silicon oxynitride, and the like. The passivation layer mayextend over and cover edge portions of contact pads in contact layer 12.Openings may be formed in portions of the passivation layer that coverthe contact pads, exposing at least a portion of the contact pads incontact layer 12. The various features of dies 10 may be formed by anysuitable method and are not described in further detail herein.Furthermore, dies 10 may be formed in a wafer (not shown) andsingulated. Functional testing may be performed on dies 10. Thus, dies10 in FIG. 1A may include only known good dies, which have passed one ormore functional quality tests.

Next, referring to FIG. 1B, dies 10 may be placed on a carrier 14.Carrier 14 may be made of a suitable material, for example, glass or acarrier tape. Dies 10 may be affixed to carrier 14 through one or moreadhesive layers (not shown). The adhesive layers may be formed of anytemporary adhesive material such as ultraviolet (UV) tape, wax, glue,and the like. In some embodiments, the adhesive layers may furtherinclude a die attach film (DAF), which may have optionally been formedunder dies 10 prior to their placement on carrier 14.

In FIG. 1C, a molding compound 16 may be used to fill gaps between dies10 and to cover top surfaces of dies 10. Molding compound 16 may includeany suitable material such as an epoxy resin, a molding underfill, andthe like. Suitable methods for forming molding compound 16 may includecompressive molding, transfer molding, liquid encapsulent molding, andthe like. For example, molding compound 16 may be dispensed between dies10 in liquid form. A curing process may then be performed to solidifymolding compound 16.

In FIG. 1D, a planarization process, such as a grinding process (e.g., achemical-mechanical polish (CMP) or mechanical grinding) or etch back,may be performed on molding compound 16 to expose contact layer 12 (andany contact pads therein) on dies 10. In a top down view of dies 10 (notshown), molding compound 16 may encircle dies 10.

FIG. 1E illustrates the formation of redistribution layers (RDLs) 18over dies 10 and molding compound 16. As illustrated by FIG. 1E, RDLs 18may extend laterally past edges of dies 10 over molding compound 16.RDLs 18 may include interconnect structures 20 formed in one or morepolymer layers 22. Polymer layers 22 may be formed of any suitablematerial (e.g., polyimide (PI), polybenzoxazole (PBO), benzocyclobuten(BCB), epoxy, silicone, acrylates, nano-filled pheno resin, siloxane, afluorinated polymer, polynorbornene, and the like) using any suitablemethod, such as, a spin-on coating technique, and the like.

Interconnect structures 20 (e.g., conductive lines and/or vias) may beformed in polymer layers 22 and electrically connected to contact layer12 of dies 10. The formation of interconnect structures 20 may includepatterning polymer layers 22 (e.g., using a combination ofphotolithography and etching processes) and forming interconnectstructures 20 (e.g., depositing a seed layer and using a mask layer todefine the shape of interconnect structures 20) in the patterned polymerlayers 22. Interconnect structures 20 may be formed of copper or acopper alloy although other metals such as aluminum, gold, and the likemay also be used. Interconnect structures 20 may be electricallyconnected to contact pads in contact layer 12 (and as a result, activedevices) in dies 10.

FIGS. 1F and 1G illustrate the formation of connectors 24 and 26 overRDLs 18. Notably, connectors 24 and 26 are formed on a same side of dies10 (i.e., on a same surface of RDLs 18). Connectors 24 and 26 may beformed of any suitable material (e.g., copper, solder, and the like)using any suitable method. In some embodiments, the formation ofconnectors 24 and 26 may first include the formation of under bumpmetallurgies (UBMs) 24′/26′ electrically connected to active devices indies 10 through RDLs 18. Connectors 24 and 26 may extend laterally pastedges of dies 10, forming fan-out interconnect structures. Thus, theinclusion of RDLs 18 may increase the number of connectors 24 and 26(e.g., input/output pads) connected to dies 10. The increased number ofconnectors 24 and 26 may allow for increased bandwidth, increasedprocessing speed (e.g., due to shorter signaling paths), lower powerconsumption (e.g., due to shorter power conduction paths), and the likein subsequently formed IC packages (e.g., package 100 of FIG. 1N).

Furthermore, connectors 24 and 26 may vary in size. For example,connectors 24 may be microbumps having a pitch of about 40 μm or morewhile connectors 26 may be controlled collapse chip connection (C4)bumps having a pitch of about 140 μm to about 150 μm. In alternativeembodiments, connectors 24 and 26 may include different dimensions.Thus, as illustrated by FIGS. 1F and 1G, connectors 24 may be formedprior to connectors 26 to allow for the size differences.

The differing sizes of connectors 24 and 26 may allow differentelectrical devices (e.g., having differently sized connectors) to bebonded to dies 10. For example, connectors 24 may be used toelectrically connect dies 10 to one or more other device dies 28 (seeFIG. 1H), and connectors 26 may be used to electrically connect dies 10to a package substrate 30 (e.g., a printed circuit board, interposer,and the like, see FIG. 1K). Furthermore, because connectors 24 and 26are formed on a same side of dies 10, the different electrical devicesmay also be bonded to a same side of dies 10. Although a particularconfiguration of dies 10 and RDLs 18 is illustrated, alternativeconfigurations may be applied (e.g., having a different number of RDLs18 and/or connectors 24/26) in alternative embodiments.

In FIG. 1H, a plurality of dies 32 may be bonded to dies 10 throughconnectors 24 (e.g., by reflowing connectors 24) to form die stacks10/32. Dies 32 may be electrically connected to active devices in dies10 through RDLs 18. In some embodiments, die stack 10/32 may includememory dies 32 (e.g., dynamic random access memory (DRAM) dies) bondedto dies 10, which may be logic dies providing control functionality formemory dies 32. In alternative embodiments, other types of dies may beincluded in dies stacks 10/32. Next, as illustrated in FIG. 1I,underfill 34 may be dispensed between dies 32 and RDLs 18 aroundconnectors 24. Underfill 34 may provide support for connectors 24.

FIG. 1J illustrates the removal of carrier 14 from die stack 10/32 usingany suitable method. For example, in an embodiment in which the adhesivebetween dies 10 and carrier 14 is formed of UV tape, dies 10 may beremoved by exposing the adhesive layer to UV light. Subsequently, diestacks 10/34 may be singulated for packaging in an IC package. Thesingulation of die stacks 10/34 may include the use of a suitablepick-and-place tool.

Next, as illustrated by FIG. 1K, each die stack 10/32 may be bonded to apackage substrate 30 through connectors 26. A reflow may be performed onconnectors 26 to bond die stack 10/32 to package substrate 30.Subsequently, as illustrated by FIG. 1L, an underfill 46 may bedispensed between die stack 10/32 and package substrate 30 aroundconnectors 26. Underfill 46 may be substantially similar to underfill34.

Package substrate 30 may be an interposer, a printed circuit board(PCB), and the like. For example, package substrate 30 may include acore 37 and one or more build-up layers 39 (labeled 39A and 39B)disposed on either side of core 37. Interconnect structures 38 (e.g.,conductive lines, vias, and/or through vias) may be included in packagesubstrate 30 to provide functional electrical purposes such as power,ground, and/or signal layers. Other configurations of package substrate30 may also be used.

Furthermore, package substrate 30 may include a cavity 36. Cavity 36 maynot extend through package substrate 30. Rather, a portion or all ofbuild-up layers 39A (e.g., build-up layers 39 disposed on a same side ofcore 37 as die stack 10/32) may be patterned to form cavity 36. Asillustrated in FIG. 1L, cavity 36 may not affect the configuration ofcore 37 and/or build-up layers 39B (e.g., build-up layers 39 disposed onan opposite side of core 37 as die stack 10/32). The configuration ofpackage substrate 30 may be designed so that active interconnectstructures 38 (e.g., power, ground, and/or signal layers in build-uplayers 39A) may be routed to avoid cavity 36. Thus, cavity 36 may notsubstantially interfere with the functionality of package substrate 30.

Package substrate 30 may be formed using any suitable method. Forexample, FIGS. 4A through 4L illustrate prospective views of variousintermediary stages of manufacturing a package substrate 30 inaccordance with various embodiments. In FIG. 4A, core 37 is provided.Core 37 may be a metal-clad insulated base material such as acopper-clad epoxy-impregnated glass-cloth laminate, a copper-cladpolyimide-impregnated glass-cloth laminate, or the like. As illustratedby FIG. 4B, cavity 36 and/or through holes 52 may be formed in core 37,for example, using a mechanical drilling or milling process. Themechanical drilling/milling process may extend through holes 52 throughcore 37. However, the mechanical drilling/milling process may not extendcavity 36 through core 37.

Next, in FIG. 4C, surfaces of through hole 52 and cavity 36 may beplated with metallic material 54, for example, using an electrochemicalplating process. In some embodiments, metallic material 54 may comprisecopper. The plating of through holes 52 may form through vias forproviding electrical connections from one side of core 37 to another.Furthermore, metallic material 54′ on surfaces of cavity 36 may act as alaser stop layer in subsequent process steps (see FIG. 4K). In FIG. 4D,cavity 36 and through holes 52 may be filled with a suitable material 56(e.g, an ink). Material 56 may fill cavity 36/through holes 52 toprovide a substantially level surface for forming one or more build-uplayers over core 37. A grinding or other planarization technique may beperformed on core 37.

As illustrated by FIGS. 4E through 4I, one or more build-up layers 39having interconnect structures 38 may be formed on either side of core37. The formation of build-up layers 39 may include plating core 37 witha conductive layer 58, for example, comprising copper as illustrated byFIG. 4E. Next, as illustrated by FIGS. 4F and 4G, conductive layer 58may be patterned to form conductive lines 38′. The patterning ofconductive layer 58 may include laminating a dry film 60 (e.g., aphotoresist) over conductive layer 58, patterning dry film 60 (e.g.,using suitable exposure techniques), and etching conductive layer 58using the patterned dry film 60 as a mask. Subsequently, dry film 60 maybe removed.

In FIG. 4H, a build-up layer 39′ may be laminated over conductive lines38′ (shown in ghost). The lamination of build-up layer 39′ may include acuring process (e.g., a heat treatment or pressing process). Openings 62may be patterned in build-up layer 39′ (e.g., through laser drilling),and openings 62 may be aligned with conductive lines 38′. As illustratedby FIG. 4I, additional conductive lines 38″ may be formed over build-uplayer 39′ using a substantially similar process as illustrated by FIGS.4E through 4H for forming conductive lines 38′ (e.g., conductive layerplating and patterning). The conductive layer plating process used forforming conductive lines 38″ may also plate openings 62 (not illustratedin FIG. 4H), thus forming conductive vias (not illustrated) forinterconnecting conductive lines 38′ and 38″ through build-up layer 39′.Conductive lines 38″ may be patterned to align with conductive viasformed in openings 62. The process steps illustrated by FIGS. 4E through4I may be repeated as desired to form any number of build-up layers(e.g., power, ground, and/or signal layers) in package substrate 30.Furthermore, although FIGS. 4E through 4I only illustrate the formationof interconnect structures 38/build-up layers 39 on one side of core 37,similar processes may be applied to form of interconnect structures38/build-up layers 39 on an opposing side of core 37.

FIG. 4J a solder resist 64 may be formed over build-up layers 39 (e.g.,on both sides of core 37). Next, as illustrated by FIG. 4K, cavity 36may be patterned in package substrate 30. The formation of cavity 36 mayinclude patterning solder resist 63 (e.g., using an exposure technique)and a laser etching build-up layers 39 using material 54′ as a laserstop layer. Thus, cavity 36 may not extend through package substrate 30.Furthermore, the patterning of solder resist 64 may pattern openings(not shown) around cavity 36 to expose interconnect structures 38 inbuild-up layers 39. These openings may be plated with a suitablematerial (e.g., nickel, aluminum, or the like) to form contact pads 66on package substrate 30. Contact pads 66 may be electrically connectedto interconnect structures 38 in build-up layers 39. Subsequently, asillustrated by FIG. 4L, connectors 68 (e.g., solder balls) may be formedon contact pads 66 for bonding with die stack 10/32.

Referring back to FIG. 1L, when die stack 10/34 is bonded to packagesubstrate 30, dies 32 may be disposed, at least partially, in cavity 36.In a top down view of package 100 (not shown), cavity 36 may encircledies 32. Thus, the bonded structure may advantageously have a relativelysmall form factor and higher bandwidth. Furthermore, dies 32 may beelectrically connected to package substrate 30 through RDLs 18 andconnectors 24/26. In some embodiments, dies 10 may include fewer or besubstantially free of through-substrate vias (TSVs) for electricallyconnecting dies 32 to package substrate 30. The reduced number of TSVsmay lower the cost of manufacturing dies 10.

Next, referring to FIG. 1M, a heat dissipation feature 40 is disposedover die 10. Heat dissipation feature 40 may be disposed on a surface ofdie 10 opposite RDLs 18, connectors 24, and dies 32. Heat dissipationfeature 40 may be a contour lid having a high thermal conductivity, forexample, between about 200 watts per meter kelvin (W/m·K) to about 400W/m·K or more, and may be formed using a metal, a metal alloy, and thelike. For example, heat dissipation feature 40 may comprise metalsand/or metal alloys such as Al, Cu, Ni, Co, combinations thereof, andthe like. Heat dissipation feature 40 may also be formed of a compositematerial, for example silicon carbide, aluminum nitride, graphite, andthe like. In some embodiments, heat dissipation feature 40 may alsoextend over surfaces of molding compound 16.

Compared to conventional 3DICs, where package substrate 30 and dies 32would be disposed on opposing sides of die 10, package 100 provides die10 with a surface 10′, which may not be used to electrically connect todies 32 or package substrate 30. Thus, heat dissipation feature 40 maybe directly disposed on surface 10′ of die 10 for improved heatdissipation.

Interfacing material 42 may be disposed between heat dissipationfeatures 40 and die 10/molding compound 16. Interfacing material 42 mayinclude a thermal interface material (TIM), for example, a polymerhaving a good thermal conductivity, which may be between about 3 wattsper meter kelvin (W/m·K) to about 5 W/m·K or more. Because the TIM mayhave good thermal conductivity, the TIM may be disposed directly between(e.g., contacting) die 10 and heat dissipation feature 40. Furthermore,interfacing material 42 may also include an adhesive (e.g., an epoxy,silicon resin, and the like) for affixing heat dissipation lid 40 to die10/molding compound 16. The adhesive used may have a better adheringability and a lower thermal conductivity than a TIM. For example, theadhesive used may have a thermal conductivity lower than about 0.5W/m·K. As such, the adhesive portions of interfacing material 42 may bedisposed over areas having lower thermal dissipation needs (e.g., oversurfaces of molding compound 16).

After the attachment of heat dissipation feature 40, a marking process(e.g., laser marking) may be performed to mark package 100. Furthermore,as illustrated by FIG. 1N, connectors 44 (e.g., ball grid array (BGA)balls) disposed on a surface of package substrate 30 opposite connectors26 and die stack 10/32. Connectors 44 may be used to electricallyconnect package 100 to a motherboard (not shown) or another devicecomponent of an electrical system.

FIG. 1N illustrates a completed package 100. Because dies 32 is disposedin a cavity 36 of package substrate 30, package 100 may have arelatively small form factor and higher bandwidth. The inclusion of RDL18 may allow for a greater number of I/O pads for die stack 10/32, whichallows various performance advantages such as increased speed, lowerpower consumption, and the like. Furthermore, package substrate 30 anddies 32 may be disposed on a same side of die 10, allowing heatdissipation feature 40 to be directly disposed on a surface of die 10for improved heat dissipation.

FIG. 2 illustrates a cross-sectional view of a package 200 in accordancewith various alternative embodiments. Package 200 may be substantiallysimilar to the package 100 where like reference numerals represent likeelements. However, heat dissipation feature 40 may include a contourring portion 40′, which may extend past die 10 and RDLs 18 to a topsurface of package substrate 30. In a top down view of package 200 (notshown), contour ring portion 40′ may encircle die 10. Contour ringportion 40′ may be formed of substantially similar materials as theremainder of heat dissipation lid 40 (e.g., a high Tk material) andprovide additional heat dissipation for package 200. Contour ringportion 40′ may be attached to package substrate 30 using any suitablemethod such as an adhesive layer 42′ disposed between contour ringportion 40′ and package substrate 30.

FIGS. 3A through 3E illustrates various intermediary steps ofmanufacturing package 300 in accordance with alternative embodiments.FIG. 3A illustrates a plurality of dies 10 having an RDL 18 andconnectors 26 formed over dies 10. The various features illustrated inFIG. 2A may be formed using substantially the same steps and besubstantially similar to the features formed in FIGS. 1A through 1Jwhere like reference numerals represent like elements. Thus, detaileddescription of the features and their formation is omitted for brevity.However, as illustrated by FIG. 2A, dies 10 (including RDLs 18 andconnectors 24) may be detached from a carrier (e.g., carrier 14) withoutthe bonding on dies 32. Furthermore, connectors 24 may not be formedover RDLs 18. Instead, the structure illustrated in FIG. 2A includesconnectors 26 on RDLs 18 may be of substantially the same size. Forexample, connectors 26 may be C4 bumps.

FIG. 3B illustrates the singulation of dies 10 (e.g., along scribe linesusing a suitable pick and place tool) and the attachment of dies 10 topackage substrate 30 through connectors 26. Notably, die 10 may bebonded to package substrate 30 prior to the attachment of dies 32 topackage 300.

The configuration of package substrate 30 in package 300 may be alteredfrom the configuration in package 100. For example, cavity 36 may bedisposed on an opposing side (rather than a same side) of packagesubstrate 30. In package 300, die 10 may be bonded to a surface 30A ofpackage substrate 30. Surface 30A may be substantially level. Packagesubstrate 30 may further include surface 30B (e.g., in cavity 36) andsurface 30C opposing die 10. Due to the inclusion of cavity 36, surfaces30B and 30C may not be substantially level. For example, in theorientation illustrated by FIG. 3B, surface 30B may be higher thansurface 30C.

The formation of package substrate 30 having cavity 36 may include thepatterning of core 37, build-up layer 39B (e.g., disposed on an opposingside of core 37 as die 10), and/or build-up layer 39A (e.g., disposed ona same side of core 37 as die 10). In various embodiments, cavity 36 maynot extend through package substrate 30.

FIG. 3C illustrates the formation of various other features of package300. For example, a reflow may be performed on connectors 26 andunderfill 46 may be dispensed around connectors 26. Connectors 44 may beattached to surface 30C of package substrate 30 opposite die 10.Furthermore, a heat dissipation feature 40 may be disposed over die10/molding compound 16. An interfacing material 42 (e.g., including aTIM and/or adhesive material) may be disposed between heat dissipationfeature 40 and die 10/molding compound 16.

Subsequently, functional tests may be performed on package 300 prior tothe attachment of dies 32. For example, electrical connections betweendie 10 and package substrate 30 may be tested. If package 300 passes thetests, dies 32 may be attached to package 300, for example, usingconnectors 24 formed as illustrated by FIG. 3D. Connectors 24 may beformed on dies 32 using any suitable method prior to attaching dies 32to package 300. By performing functional tests on package 300 prior tothe attachment of dies 32, dies 32 may be attached to only to known goodpackages. Packages that fail the functional tests may not have dies 32attached thereto. Thus, cost savings may be incurred by avoidingattachment of dies 32 to failed packages.

Connectors 24 (e.g., microbumps) may be formed on dies 32 using anysuitable method. Connectors 24 may be of a different size thanconnectors 26, and connectors 24 may be attached to contact pads onpackage substrate 30. Connectors 24 may be electrically connect dies 32to die 10 through interconnect structures 38 in package substrate 30(e.g., interconnect structures 38′), connectors 26, and RDLs 18.

Dies 32 may be disposed in cavity 36 of package substrate. In package300, dies 32 and die 10 may be disposed on opposing sides of packagesubstrate 30. Attaching dies 32 may include flipping package 300 (e.g.,so that connectors 24 face upwards) and aligning dies 32 in cavity 36. Areflow may be performed on connectors 24 (e.g., to electrically connectdies 32 to die 10/package substrate 30), an underfill 34 may bedispensed around connectors 24.

The configuration of package 300 allows for a heat dissipation feature(e.g., heat dissipation feature 70) to be disposed on a surface dies 32.An interfacing material 72 may be disposed between heat dissipationfeature 70 and dies 32, and interfacing material 72 may be in physicalcontact with dies 32. Heat dissipation feature 70 and interfacingmaterial 72 may be substantially similar to heat dissipation feature 40and interfacing material 42, respectively. Thus, an alternativemanufacturing process may be used to form package 300.

FIGS. 5A and 5B illustrate cross-sectional views of semiconductorpackages 400 and 500, respectively. Packages 400 and 500 may besubstantially similar to package 100 where like reference numeralsrepresent like elements. However, packages 400 and 500 may furtherinclude multiple dies 10 (labeled 10A and 10B). Dies 10A and 10B may bepart of a same fan-out package. For example, dies 10A and 10B may besurrounded by molding compound 14, and RDLs 18 may be formed on asurface of dies 10A and 10B. RDLs 18 may electrically connect dies 10Aand 10B to dies 32. Furthermore, dies 10A and 10B may be substantiallylevel. The formation of dies 10A and 10B may be substantially similar tothe process illustrated in FIGS. 1A through 1J although singulation maybe performed at different locations (e.g., scribe lines for a pick andplace tool may be configured at different locations). In someembodiments, die 32 may be disposed in a cavity formed in substrate 30(as illustrated by FIG. 5A). In other embodiments, die 32 may bedisposed in a through-hole 74 in substrate 30 (as illustrated by FIG.5B). Through hole 74 may be formed in substrate 30, for example, using alaser drilling process.

FIGS. 6A and 6B illustrate cross-sectional and top down views of apackage substrate 150 in accordance with some alternative embodiments.FIG. 6A illustrates a cross-sectional view while FIG. 6B illustrates atop down view. Package substrate 150 includes a coreless build-upportion 316 and a laminate portion 318 over the coreless build-upportion 316. In various embodiments, coreless build-up portion 316 hasthin profile (e.g., due to the lack of a core), which may be integratedin advanced node applications for achieving a thin overall packageprofile.

Coreless build-up portion 316 includes one or more embedded patternprocess (EPP) layers, such as one or more build-up layers 106 (e.g.,dielectric layers) comprising conductive features 102, 104, and 108.Conductive features 102 may be at least partially exposed at a topsurface 316A of coreless build-up portion 316, and exposed portions ofconductive features 102 may be used as bump pads to bond a die (e.g.,die 202 in FIG. 7A) to package substrate 150. In some embodiments,conductive features 102 may have a pitch of about 40 μm to about 150 μmfor fine pitch bonding. Other dimensions for conductive features 102 mayalso be employed in other embodiments depending on substrate design.

Furthermore, conductive features 102 may be electrically connected toconductive features 104. For example, one or more interconnect layers(not illustrated) having conductive interconnect structures (e.g.,conductive lines and/or vias) electrically connecting conductivefeatures 102 and 104 may be formed in coreless build-up portion 316.Alternatively, conductive features 102 may be conductive trace lines,which may be physically connected to conductive features 104. Conductivefeatures 104 may be electrically connected to vias 108, which may beused to provide electrical connection to contact pads 110 on a bottomsurface 316B of coreless build-up portion 316. For example, in theillustrated embodiment, vias 108 extend through dielectric layer 106. Asolder resist 122B may be disposed on bottom surface 316B of corelessbuild-up portion 316, and openings in solder resist 122B may exposecontact pads 110. Subsequently, external connectors (e.g., ball gridarray (BGA) balls, see FIG. 7A) may be disposed on contact pads 110.

Laminate portion 318 may be disposed over coreless build-up portion 316.In various embodiments, laminate portion 318 includes vias 116 extendingthrough a dielectric layer 112 and core 114. Dielectric layer 112 may beused to bond core 114 to coreless build-up portion 316. Laminate portion318 further includes a cavity 120, where a die (e.g., die 202 in FIG.7A) bonded to conductive features 102 may be disposed. In someembodiments, cavity 120 may have a lateral dimension W greater thanabout 30 μm, and a vertical dimension T greater than about 30 μm.

Laminate portion 318 further includes contact pads 118, which may beused to bond another package feature such as another device die, anotherdevice package (e.g., package 204 of FIG. 7A), and the like. In someembodiments, contact pads 118 may have a pitch of about 200 μm to about400 μm for fine pitch bonding. Other dimensions for contact pads 118 mayalso be employed depending on package design. As illustrated in atop-down view of package substrate 150 of FIG. 6B, contact pads 118 (andthe other underlying features of laminate portion 318) may encirclecavity 120 and exposed conductive features 102.

Vias 116 are electrically connected to conductive features 104, and thedimension of vias 116 may be selected to provide a sufficient stand-offheight (e.g., vertical dimension T) so that die 202 may be disposed oncavity 120. The use of vias 116 and contact pads 118 may be used in lieuof traditional large, solder balls for bonding another device package,which reduces the risk of solder bridging and improves yield.Furthermore, core 114 of laminate portion 318 may provide improvedrigidity for warpage control in package substrate 150. A solder resist122A may be disposed over core 114, and openings may be patterned insolder resist 122 to expose contact pads 118.

FIGS. 7A and 7B illustrate cross-sectional views of a package 250 havinga package substrate 150 as illustrated in FIGS. 6A and 6B. A die 202 maybe disposed in cavity 120 and bonded to exposed conductive features 102through connectors 206 (e.g., BGA balls, microbumps, C4 bumps, and thelike). In some embodiments (as illustrated by FIG. 7A), an underfill 212may be dispensed around connectors 206. In other embodiments (asillustrated by FIG. 7B), a molding compound 214 may be dispensed arounddie 202 and at least partially fill cavity 120. Die 202 may be exposedby molding compound 214 (as illustrated by FIG. 7B) or molding compound214 may cover die 202 (not shown).

Furthermore, another device package 204 may be bonded to contact pads118 by connectors 208 (e.g., BGA balls, microbumps, C4 bumps, and thelike). Device package 204 may include various features (not individuallyillustrated), such as one or more device dies, which may or may not beconfigured in a die stack, and interconnect structures (e.g., variousfan-out RDLs, through-vias, package substrates, interposers, and thelike). In some embodiments, package 204 may be a memory package such asa dynamic random access memory (DRAM) package, and the like. In theillustrated embodiments, laminate portion 318 of package substrate 150provides a sufficient standoff height so that die 202 may be disposed incavity 120 without contacting package 204. External connectors 210 maybe disposed on contact pads 110 on a bottom surface 316B of corelessbuild-up portion 316. External connectors 210 may be used to bondpackage 250 to another package component such as an interposer, packagesubstrate, printed circuit board, and the like.

FIGS. 8A through 8N illustrates cross-sectional views of variousintermediary steps of manufacturing a package substrate 150 inaccordance with some embodiments. The manufacturing of substrate 150 maybe divided into two logical stages. In the first stage (as illustratedby FIGS. 8A through 8G), a coreless build-up portion 316 is formed usinga carrier 302 for temporary structural support. Subsequently, in thesecond stage (as illustrated by FIGS. 8H through 8M), laminate portion318 having a cavity 120 is formed over coreless build-up portion 316.

Referring now to FIG. 8A, a carrier substrate 302 having seed layers 304disposed on opposing surfaces is provided. Carrier substrate 302provides temporary mechanical and structural support for the processingof build-up layers during subsequent processing steps. In someembodiments, carrier 302 may comprise an organic core material such asepoxy-impregnated glass-fiber laminate, polymer-impregnated glass-fiberlaminate, and the like. Alternatively, carrier 302 may comprise othermaterials, such as, stainless steel, glass, and the like.

Seed layers 304 comprising a conductive material (e.g., copper) areformed on opposing surfaces of carrier 302. Seed layers 304 are formedusing any suitable process. For example, when carrier 302 comprises anorganic core material, seed layers 304 may be formed by laminating aconductive foil (e.g., copper foil) on opposing sides of carrier 302. Asanother example, seed layers 304 may be formed using plating orsputtering processes when carrier 302 comprises stainless steel, glass,and the like.

As further illustrated by FIG. 8A, patterned photoresists 306 are formedon seed layers 304 (e.g., a patterned photoresist 306 is formed on bothsides of carrier 302). For example, photoresists 306 may be coated orlaminated as blanket layers on respective seed layers 304. Next,portions of photoresists 306 are exposed using a photo mask (not shown).Exposed or unexposed portions of photoresists 306 are then removeddepending on whether a negative or positive resist is used. Theresulting patterned photoresists 306 may include openings 308, exposingrespective seed layers 304.

FIG. 8B illustrates the filling of openings 308 with a conductivematerial such as copper, silver, gold, and the like to form conductivefeatures 102 and 104. Conductive features 102 and 104 may vary indimension depending on substrate design. For example, conductivefeatures 102 may be used as bump pads for bonding a device die 202 insubsequent process steps (see e.g., FIG. 3N) while conductive features104 may be used as contacts for the formation of through-vias (e.g.,through vias 116 of FIG. 31) in subsequent process steps. Thus,conductive features 102 may have a smaller pitch and/or width comparedto conductive features 104.

The filling of openings 308 may include plating openings 308 (e.g.,electro-chemical plating) with the conductive material using seed layers304. The conductive material may overfill openings 308, and aplanarization may be performed to remove excess portions of theconductive material over photoresists 306. Planarization may include achemical mechanical polish (CMP) process, mechanical grinding process,or other etch back technique, for example. Subsequently, a plasma ashingand/or wet strip process may be used to remove photoresists 306.Optionally, the plasma ashing process may be followed by a wet dip in asulfuric acid (H₂SO₄) solution to clean the structure and removeremaining photoresist material.

Next, as illustrated by FIG. 8C, build-up layers 106 are formed on bothsides of carrier 302. For example, each build-up layer 106 may bedisposed over a corresponding seed layer 304 and conductive features102/104. Build-up layers 106 may comprise a dielectric material such asa prepreg (e.g., FR4 epoxy resin, M6 epoxy resin, and the like),Ajinomoto build-up film (ABF), and the like, which may be applied bylamination. For example, a vacuum laminator may be used to disposedielectric material on carrier 302, and an oven curing process may beapplied to adhere the dielectric material to seed layers 304 andconductive features 102/104. As another example, a hot press process mayapply the dielectric material to seed layers 304 and conductive features102/104 under suitable heat and/or pressure conditions for a suitableduration (e.g., one to two hours) to form build-up layers 106.

Alternatively, or additionally, build-up layers 106 may comprise silicondioxide, silicon nitride, silicon oxynitride, an oxide, a nitrogencontaining oxide, aluminum oxide, lanthanum oxide, hafnium oxide,zirconium oxide, hafnium oxynitride, a combination thereof, and/or othermaterials. Build-up layers 106 may be formed by sputtering, spin-oncoating, CVD, low-pressure CVD, rapid thermal CVD, atomic layer CVD,and/or plasma enhanced CVD, perhaps utilizing tetraethyl orthosilicateand oxygen as a precursor. Build-up layers 106 may also be formed by anoxidation process, such as wet or dry thermal oxidation in an ambientenvironment comprising an oxide, water, nitric oxide, or a combinationthereof, and/or other processes.

As further illustrated by FIG. 8C, build-up layers 106 may be patternedto include openings 308 exposing conductive features 104. The patterningof build-up layers 106 may include any suitable process such as laserdrilling, a combination of photolithography and etching, and the like.

FIG. 8D illustrates the formation of additional conductive features,such as conductive vias 108 and contact pads 110. Conductive vias 108may be formed by filling openings 308 with a conductive material. In anembodiment, the conductive material may be formed by depositing a seedlayer on sidewalls of openings 308. The seed layer (not shown) may beformed of copper, nickel, gold, any combination thereof and/or the like.Once the seed layer has been deposited in the opening, a conductivematerial, such as tungsten, titanium, aluminum, copper, any combinationsthereof and/or the like, is filled into the opening, using, for example,an electro-chemical plating process. The conductive material mayoverfill openings 308, and excess materials (e.g., excess conductivematerials) are removed from surfaces of build-up layers 106. In someembodiments a planarization process, such as a CMP process, mechanicalgrinding process, or other etch-back technique is used to remove theexcess materials, thereby forming vias 108.

Contact pads 110 may also be formed on build-up layers 106. Contact pads110 may be formed using a substantially similar process as conductivefeatures 102/104. For example, a patterned photoresist (not shown) maybe formed over build-up layers 106. Openings in the patternedphotoresist may be used to define a shape of contact pads 110. Suchopenings may be filled with a conductive material, for example, by firstdepositing a seed layer (not shown) on bottom surfaces and/or sidewallsof such openings and filling the openings using an electro-chemicalplating process. Contact pads 110 may be electrically connected tocontacts 104 by vias 108, and external connectors (e.g., solder balls)may be disposed on contact pads 110 (see e.g., FIG. 2B). Thus, twocoreless build-up layer portions 316 are formed on both sides of carrier302. Although each build-up layer portion 316 only contains a singlebuild-up layer 106, in alternative embodiments, any number of build-uplayers having conductive features (e.g., conductive lines and/or vias)may be formed depending on substrate design. Furthermore, although FIGS.8A through 8D illustrate the simultaneous formation of two build-uplayer portions 316 on carrier 302, in alternative embodiments, a singlecoreless build-up layer portion 316 may be formed on a single side ofcarrier 302.

FIGS. 8E and 8F illustrate the removal of a build-up layer portion 316(labeled 316′) from carrier 302. In some embodiments, build-up layerportion 316′ is removed using mechanical force. For example, referringto FIG. 8E, mechanical tools 310 are wedged between carrier 302 and aseed layer 304. Mechanical tools 310 create a separation between carrier302 and seed layer 304 at edge portions of carrier 302. Next, vacuumclamps 312 may be used to apply mechanical force to opposing sides ofcarrier 302. Vacuum clamps 312 may apply mechanical force in opposingdirections (as indicated by arrows 314), and the mechanical forcephysically separates build-up layer portion 316′ from carrier 302. Insome embodiments, build-up layer portion 316′ may be separated fromcarrier 302 without significantly damaging other features in theillustrated structure due the relatively weak adhesive bond betweencarrier 302 and seed layer 304. For example, seed layer 304 may beapplied to carrier 302 using a relatively weak lamination process (e.g.,without undergoing an extensive cure). The weakness of the bond betweencarrier 302 and seed layer 304 may further be exploited by theseparation of carrier 302 and seed layer 304 at edge portions due to theapplication of mechanical tools 310. Thus, build-up portion 316′ may beremoved from carrier 302 as illustrated by FIG. 8F. The build-up portion316 above carrier 302 may also be removed using a similar process.

Referring next to FIG. 8G, seed layer 304 may be removed using asuitable etching process, for example. The etching of seed layer 304 mayfurther recess conductive features 102 and 104 from a top surface ofdielectric layer 106. In some embodiments, the etching of seed layer 304may use a suitable chemical etchant depending on the material of seedlayer 304. For example, when seed layer 304 comprises copper, suitablechemical etchants include a sulfuric acid (H₂SO₄) or hydrogen peroxide(H₂O₂) based chemical etchant. Thus, conductive features 102 and 104 maybe exposed at a top surface 316A of coreless build-up portion 316.

FIGS. 8H through 8M illustrate various intermediary steps of forminglaminate portion 318 over coreless build-up portion 316. First,referring to FIG. 8H, a core 114 may be bonded to coreless build-upportion 316 by a patterned dielectric layer 112. For example, an uncureddielectric layer 112 comprising a suitable material such as a prepreg(e.g., FR4 epoxy resin, M6 epoxy resin, and the like), ABF, and thelike, which may be applied over coreless build-up portion 316.Dielectric layer 112 may be patterned to include a cavity 120, which maybe aligned with exposed conductive features 102. In some embodiments,cavity 120 may be pre-patterned (e.g., using a punching process) indielectric layer 112 prior to the disposition of dielectric layer 112 oncoreless build-up portion 316. Other methods for patterning dielectriclayer 112 (either before or after being disposed on coreless build-upportion 316) may also be employed. Next, core 114 may be disposed overdielectric layer 112, and a curing process may be applied to adhere core114 to coreless build-up portion 316. Core 114 may comprise an organiccore material such as epoxy-impregnated glass-fiber laminate,polymer-impregnated glass-fiber laminate, and the like, for example.

FIGS. 8I and 8J illustrate the formation of conductive features indielectric layer 112 and core 114. First, in FIG. 8I, openings 320 maybe patterned in core 114 and dielectric layer 112 using a laser drillingprocess, for example. Openings 320 may extend through core 114 anddielectric layer 112 to expose conductive features 104.

FIG. 8J illustrates the formation of additional conductive features,such as conductive vias 116 and contact pads 118. Conductive vias 118may be formed by filling openings 320 with a conductive material. In anembodiment, the conductive material may be formed by depositing a seedlayer on sidewalls of openings 320. The seed layer (not shown) may beformed of copper, nickel, gold, any combination thereof and/or the like.Once the seed layer has been deposited in the opening, a conductivematerial, such as tungsten, titanium, aluminum, copper, any combinationsthereof and/or the like, is filled into the opening, using, for example,an electro-chemical plating process. In some embodiments, the conductivematerial may not completely fill openings 320. For example, FIG. 8Killustrates a top-down view an example via 116, which may include ahollow center portion 322. In other embodiments, the conductive materialcompletely or substantially fills openings 320. Vias 116 may extendthrough core 114 and dielectric layer 112 to electrically connect toconductive features 104 of coreless build-up portion 316.

Contact pads 118 may also be formed over core 114. Contact pads 118 maybe formed using a substantially similar process as contact pads 110. Forexample, a patterned photoresist (not shown) may be formed over core114. Openings in the patterned photoresist may be used to define a shapeof contact pads 118. Such openings may be filled with a conductivematerial, for example, by first depositing a seed layer (not shown) onbottom surfaces and/or sidewalls of such openings and filling theopenings using an electro-chemical plating process. Contact pads 118 maybe electrically connected to contacts 104 by vias 116, and in contactpads 118 may be used to bond other packages (e.g., package 204 of FIG.7A) to substrate 150.

Next, in FIG. 8L, solder resists 122A and 122B are formed on packagesubstrate 150. Solder resist 122A may be disposed over core 114 andsolder resist 122B may be disposed on a bottom surface of corelessbuild-up portion 316. Solder resists 122A and 122B may be patterned toexpose at least portions of contact pads 118 and 110, respectively.Solder resists 122A and 122B may comprise a heat-resistant coatingmaterial, and may aid in protecting the various layers of packagesubstrate 150.

In FIG. 8M, a portion of core 114 over cavity 120 (labeled 114′) isremoved to expose conductive features 102 and expanding cavity 120. Theremoval of core portion 114′ may be done using any suitable method, suchas laser drilling, mechanical drilling, and the like. Process conditions(e.g., time of mechanical drilling, focus of laser drilling, and thelike) may be controlled so that core portion 114′ may be removed withoutdamaging underlying features of package substrate 150. In someembodiments, a protective layer (e.g., comprising a metal, not shown)may be included under core portion 114′ to protect underlying featuresduring the removal of core portion 114′. After core portion 114′ isremoved, the protective layer may also be removed to expose conductivefeatures 102. Thus, package substrate 150 having a coreless build-upportion 316 and a laminate portion 318 is formed. In subsequent processsteps, a die 202 may be disposed on cavity 120 and bonded to conductivefeatures 102 as illustrated by FIG. 8N. Additional features, such asthose described in FIGS. 7A, 7B, and 9A through 11B, may then be formedaround package substrate 150 and die 202.

FIGS. 9A and 9B illustrate cross-sectional views of a package 450 havinga package substrate 150 according to some alternative embodiments.Package 450 is similar to package 250 where like reference numeralsindicate like elements. A die 202 may be disposed in cavity 120 andbonded to exposed conductive features 102 through connectors 206 In someembodiments (as illustrated by FIG. 9A), an underfill 212 may bedispensed around connectors 206. In other embodiments (as illustrated byFIG. 9B), a molding compound 214 may be dispensed around die 202 and atleast partially fill cavity 120. Die 202 may be exposed by moldingcompound 214 (not shown) or molding compound 214 may cover die 202 (asillustrated by FIG. 9B).

Furthermore, in the alternative package configuration of FIGS. 9A and9B, another device package 204 may be disposed on an opposing side ofcoreless build-up portion 316 as die 202. For example, device package204 may be bonded to contact pads 110, not 118, by connectors 208.Because cavity 120 does not extend through coreless build-up portion316, contact pads 110 may be disposed in a full grid array on bottomsurface 316B (illustrated as a top surface in the orientation shown inFIGS. 9A and 9B) of coreless build-up portion 316. Thus, additionalcontacts may be provided for bonding package 204. In the illustratedembodiments, laminate portion 318 of package substrate 150 provides asufficient standoff height so that die 202 may be disposed in cavity120. External connectors 210 may be disposed on contact pads 118 on asame side of package substrate 150 as die 202. External connectors 210may be used to bond package 450 to another package component such as aninterposer, package substrate, printed circuit board, and the like.

FIG. 10 illustrate a cross-sectional view of a package 550 having apackage substrate 150 according to some alternative embodiments. Package550 is similar to package 450 where like reference numerals indicatelike elements. However, in package 550, an interposer 216 may be bondedto contact pads 110 by connectors 218 (e.g., BGA balls, C4 bumps,microbumps, or the like) instead of another device package 204.Interposer 216 may include conductive features, such as through-vias222. Other package components (e.g., dies 220, another device package,and the like) may be bonded to interposer 216, and conductive features(e.g., through vias 222) in interposer 216 may electrically connect theother package components to package substrate 150.

FIGS. 11A and 11B illustrate cross-sectional views of intermediary stepsof manufacturing a package 650 having a package substrate 150 accordingto some alternative embodiments. Package 650 is similar to package 450where like reference numerals indicate like elements. Referring first toFIG. 11A, presolder 224 may be disposed on a subset of contact pads 110(labeled 110A). Other contact pads 110B may remain exposed. Thepresolder may be disposed in openings defined by solder resist 122B.Subsequently, presolder 224 may be used to bond another device die 220to contact pads 110A. Contacts 226 (e.g., BGA balls, C4 bumps,microbumps, and the like) on die 220 may be bonded with presolder 224.Alternatively, presolder 224 may be omitted, and contacts 226 may bedirectly bonded on contacts pads 110A.

After die 220 is bonded, an underfill 228 may be dispensed between die220 and package substrate 150 as illustrated by FIG. 11B. As furtherillustrated by FIG. 11B, another package component (e.g., package 204)may be bonded to contact pads 110B by solder balls 230. In someembodiments, the bonding of package 204 may include first forming apresolder on contact pads 110B. Solder balls 230 may be sufficientlylarge to provide a sufficient standoff height so that die 220 may bedisposed between package 204 and package substrate 150.

FIG. 12 illustrates a process flow 700 for forming a package (e.g.,package 250, 450, 550, or 650) in accordance with some embodiments. Instep 702, a coreless build-up portion (e.g., coreless build-up portion316) is formed having exposed conductive features (e.g., bump pads 102and contact pads 104). The formation of the coreless build-up portionmay be in accordance with the steps illustrated by FIGS. 8A through 8G.For example, various build-up layers having conductive features may beformed on a temporary core, which provides structural support. Thebuild-up layers may then be separated from the core (e.g., usingmechanical force). A seed layer may then be removed to expose conductivefeatures (e.g., features 102 and 104) in the build-up layers.

Next, in step 704, a core (e.g., core 114) is attached to the corelessbuild-up portion. In some embodiments, the core is attached using adielectric layer (e.g., dielectric layer 112), which may be patterned toinclude a cavity (e.g., cavity 120). In step 706, through vias (e.g.,vias 116) are formed extending through the core. The through vias may beelectrically connected to a first subset of the conductive features(e.g., contact pads 104). Contact pads (e.g., contact pads 118) may beformed on the through vias in step 708.

In step 710, a center portion (e.g., portion 116′) of the core isremoved to form a cavity 120. The cavity may be defined by remainingportions of the core, which may encircle the cavity. A second subset ofthe conductive features (e.g., bump pads 102) may be exposed by cavity120. Thus, a package substrate (e.g., substrate 150) is formed inaccordance with some embodiments. Subsequently, in step 712, a die(e.g., die 202) may be bonded to the second subset of the conductivefeatures (e.g., bump pads 102). The die may be disposed in the cavity.In step 714, connectors may be formed on the contact pads on the throughvias. In some embodiments, the other package component (e.g., package204) may be bonded to the contact pads on the through vias. In otherembodiments, another package component (e.g., package 204, interposer216, die 220, and the like) may be bonded to contact pads formed on anopposing side of the coreless build-up portion as the cavity.

Thus, as described above, a package substrate may include a cavity. Afirst die may be bonded to the package substrate. Where the cavity maybe on the same side of the package substrate as the first die or on anopposing side of the package substrate as the first die. One or moresecond dies may be bonded to the package substrate and the first die,and the second dies may be disposed in the cavity. The second die may bebonded directly to the first die, or the second die may be bondeddirectly to the package substrate. Thus, the configuration of thepackage substrate allows for a package having a relatively thin formfactor. Furthermore, the configuration of the dies in the package mayallow for relatively simplistic heat dissipation elements to be attachedto at least the first die.

In accordance with an embodiment, a device package includes a packagesubstrate and a first and a second die bonded to the package substrate.The package substrate includes a build-up portion comprising a firstcontact pad and a plurality of bump pads. The package substrate furtherincludes an organic core attached to the build-up portion, a through-viaelectrically connected to the first contact pad and extending throughthe organic core, a second contact pad on the through-via, a connectoron the second contact pad, and a cavity extending through the organiccore. The cavity exposes the plurality of bump pads, and the first dieis disposed on the cavity and is bonded to the plurality of bump pads.

In accordance with another embodiment, a method for forming a devicepackage includes providing a package substrate and bonding a first and asecond die to the package substrate. The package substrate includes abuild-up portion having a plurality of bump pads, an organic coreattached to the build-up portion, a through-via extending through theorganic core, and a cavity extending through the organic core. Thethrough-via is electrically connected to a conductive feature in thebuild-up portion, and, and the plurality of bump pads are exposed by thecavity. Bonding the first die includes bonding the first die to theplurality of bump pads, wherein the first die is at least partiallydisposed in the cavity.

In accordance with yet another embodiment, a method for forming a devicepackage includes forming a build-up portion having a first contact padand a plurality of bump pads. The method further includes attaching anorganic core to the build-up portion, patterning an opening extendingthrough the organic core, exposing the first contact, forming athrough-via in the opening and contacting the first contact pad, forminga second contact pad on the through-via, and forming a connector on thesecond contact pad. Subsequently, a portion of the organic core isremoved to form a cavity extending through remaining portions of theorganic core. The cavity exposes the plurality of bump pads.

The foregoing outlines features of several embodiments so that thoseskilled in the art may better understand the aspects of the presentdisclosure. Those skilled in the art should appreciate that they mayreadily use the present disclosure as a basis for designing or modifyingother processes and structures for carrying out the same purposes and/orachieving the same advantages of the embodiments introduced herein.Those skilled in the art should also realize that such equivalentconstructions do not depart from the spirit and scope of the presentdisclosure, and that they may make various changes, substitutions, andalterations herein without departing from the spirit and scope of thepresent disclosure.

What is claimed is:
 1. A device package comprising: a package substratecomprising: a build-up portion comprising a first contact pad and aplurality of bump pads at a first surface; an organic core attached tothe build-up portion; a through-via extending through the organic core,wherein the through-via is electrically connected to the first contactpad; a second contact pad on the through-via; a connector on the secondcontact pad; and a cavity extending through the organic core, whereinthe cavity exposes the plurality of bump pads; a first die disposed inthe cavity, wherein the die is bonded to plurality of bump pads; and asecond die bonded to the package substrate.
 2. The device package ofclaim 1, wherein a second device package comprising the second die isbonded to package substrate by the connector.
 3. The device package ofclaim 1, wherein the package substrate further comprises a third contactpad at an opposing surface of the build-up portion as the first surface,and wherein a second device package comprising the second die is bondedto the third contact pad.
 4. The device package of claim 1, furthercomprising an interposer bonded to the package substrate, wherein thesecond die is bonded to an opposing side of the interposer as thepackage substrate.
 5. The device package of claim 1, further comprisinga third device package bonded to the package substrate, wherein thesecond die is disposed between the third device package and the packagesubstrate.
 6. The device package of claim 1, further comprising anunderfill dispensed between the first die and the package substrate. 7.The device package of claim 1, further comprising a molding compoundsurrounding the first die in the cavity.
 8. The device package of claim1, wherein the organic core is attached to the build-up portion by adielectric layer, wherein the cavity extends through the dielectriclayer.
 9. The device of claim 1, wherein the build-up portion is acoreless build-up portion.
 10. A method for forming a device packagecomprising: providing a package substrate comprising: a build-up portioncomprising a plurality of bump pads; an organic core attached to thebuild-up portion; a through-via extending through the organic core,wherein the through-via is electrically connected to a conductivefeature in the build-up portion; and a cavity extending through theorganic core, wherein the plurality of bump pads are exposed by thecavity; bonding a first die to the plurality of bump pads, wherein thefirst die is at least partially disposed in the cavity; and bonding asecond die to the package substrate.
 11. The method of claim 10, whereinbonding the second die comprises: providing a second device packagecomprising the second die; and bonding the second device package to thepackage substrate.
 12. The method of claim 11, wherein bonding thesecond device package comprises bonding the second device package to asame side of the package substrate as the first die.
 13. The method ofclaim 11, wherein bonding the second device package comprises bondingthe second device package to an opposing side of the package substrateas the first die.
 14. The method of claim 10, wherein the build-upportion is substantially free of an organic core.
 15. A method forforming a device package comprising: forming a build-up portioncomprising a first contact pad and a plurality of bump pads; attachingan organic core to the build-up portion; patterning an opening extendingthrough the organic core, exposing the first contact; forming athrough-via in the opening and contacting the first contact pad; forminga second contact pad on the through-via; forming a connector on thesecond contact pad; and removing a portion of the organic core to form acavity extending through remaining portions of the organic core, whereinthe cavity exposes the plurality of bump pads.
 16. The method of claim15, wherein forming the build-up portion comprises: providing carrierhaving a seed layer disposed on a surface of the carrier; forming thefirst contact pad and the plurality of bump pads on the seed layer;forming a first dielectric layer on the first contact pad, the pluralityof bump pads, and the seed layer; removing the carrier; and removing theseed layer to expose the first contact pad and the plurality of bumppads.
 17. The method of claim 16, wherein removing the seed layercomprises an etching process.
 18. The method of claim 16, whereinforming build-up portion comprises simultaneously forming a secondbuild-up portion on an opposing side of the carrier as the build-upportion.
 19. The method of claim 15, wherein attaching the organic corecomprises: disposing an uncured dielectric layer over the build-upportion, wherein the uncured dielectric layer is patterned to expose theplurality of bump pads; disposing the organic core over the uncureddielectric layer; and performing a curing process to adhere the organiccore to the build-up portion.
 20. The method of claim 15, furthercomprising bonding a die to the plurality of bump pads, wherein the dieis disposed in the cavity.